JP5416052B2 - Solid-state NMR apparatus, sample holder for solid-state NMR apparatus, and solid-state NMR measurement method - Google Patents

Description

  The present invention relates to a solid high-resolution NMR apparatus, a sample holder for a solid NMR apparatus, and a solid NMR measurement method used when measuring a nuclear magnetic resonance (NMR) spectrum of a disk-shaped solid sample such as a wafer.

  The NMR apparatus applies a static magnetic field to a nucleus having a spin magnetic moment, generates a Larmor precession in the spin magnetic moment, and irradiates and resonates with a high frequency of the same frequency as the precession. , An analyzer for detecting a signal of a nucleus having the spin magnetic moment.

  There are two types of samples to be measured by NMR: solution samples and solid samples. Among them, in the case of a solution sample, an extremely sharp NMR spectrum is often obtained. Therefore, it is widely used to analyze a molecular structure of a chemical substance using the obtained high-resolution NMR spectrum as a weapon.

  On the other hand, in the NMR spectrum of a solid sample, interactions that are eliminated by rotational Brownian motion in solution, such as dipole interactions, appear as they are, resulting in an extremely wide spectrum linewidth and chemical shift. The term is obscured. For this reason, in the NMR spectrum, the signal peak of each part of the measurement molecule could not be separated, and as a result, the solid NMR method was considered unsuitable for molecular structure analysis.

A method for overcoming this phenomenon and obtaining a sharp solid state NMR spectrum was described in 1958 by E.I. R. Discovered by Andrew. The principle is that the sample tube is tilted by about 54.7 ° from the direction of the static magnetic field B ₀ and rotated at a high speed to remove the anisotropic interaction and extract the chemical shift term. This is called the Magic Angle Spinning method.

  FIG. 1 shows a block diagram of a mechanism for adjusting the angle of the rotation axis of the sample tube in the solid-state NMR measurement apparatus. In the figure, 1 indicates the entire probe. Reference numeral 2 denotes a sample tube (rotor) for storing a sample. The sample tube is placed in a sample rotation mechanism (stator) having an air bearing 3 and a sample tube 2 is used by using a medium such as compressed air or nitrogen gas. Rotate at high speed.

  4 is a movable mechanism such as a gear for changing the angle of the stator 3. Reference numeral 5 denotes, for example, a shaft that is connected to the movable mechanism 4 and operates the movable mechanism 4 from the outside. A knob 6 is connected to the shaft 5 and is accessed by a human when the magic angle is actually adjusted.

By rotating the sample tube around the magic angle (54.7 °) with respect to the static magnetic field B ₀ , the chemical shift anisotropy can be eliminated and the line width of the NMR spectrum can be narrowed. It is important to adjust the magic angle.

  In recent years, as a result of the development of semiconductor film formation techniques, attempts have been started to evaluate film physical properties by measuring a thin film sample on a wafer by a solid-state NMR method. The most basic method is that a thin film sample is scraped off from a substrate and packed in a sample tube, and this is measured with a normal solid-state NMR apparatus (Non-patent Document 1). However, this method tends to result in a question of the reliability of the data obtained because it results in the film being modified.

  Therefore, a special solid-state NMR apparatus has been proposed that can perform solid-state high-resolution NMR measurement without destroying a thin film sample such as a semiconductor wafer (Patent Document 1). Since this technique is an important technique on which the present invention is based, it will be briefly described with reference to the drawings.

FIG. 2 shows a solid-state high-resolution NMR apparatus for wafer measurement disclosed in the open utility model No. 62-79151. In the figure, in the static magnetic field H ₀ generated by the magnet 11, a sample holding table 12 having a sample holding surface inclined by about 35.3 ° with respect to the static magnetic field is disposed. Similarly, a disk-shaped sample 13 is placed.

  Reference numeral 14 denotes a rotating shaft attached to the sample holder, and is supported by an air bearing 16 to which pressurized air is sent from the compressor 15. At the end of the air bearing, there is provided a nozzle 19 that applies rotational force to the shaft by blowing pressurized air from the compressor 18 to a plurality of grooves 17 provided on the peripheral surface of the shaft 14. Therefore, the sample holder is rotated at high speed while maintaining an inclination angle of about 35.3 ° with respect to the static magnetic field.

  In this way, the transmission / reception coil 21 attached to the tip of the arm 20 is disposed in close proximity to the center of rotation of the sample 13 that rotates at a high speed together with the holding table. Reference numeral 22 denotes a base on which the arm 20 is rotatably mounted, 23 is a transmission circuit for supplying an observation pulse to the transmission / reception coil 21, and 24 is a reception for taking out a resonance signal induced in the transmission / reception coil 21. The circuit 25 is a computer that processes the extracted resonance signal.

  In such a configuration, since the sample 13 is rotated on a plane inclined by about 35.3 ° with respect to the static magnetic field, the axis of rotation is inclined by about 54.7 ° with respect to the static magnetic field, and the magic angle. Will be set to.

  Then, an observation pulse (pulse train) is transmitted from the transmission circuit 23 to the transmission / reception coil 21 arranged close to the rotation center portion of the sample surface to irradiate the sample, and after irradiation, a resonance signal induced in the transmission / reception coil 21 is received by the reception circuit 24. If it is taken out from the above, NMR measurement can be performed on the center of rotation of the sample surface.

  If the transmitting / receiving coil 21 is moved along the rotating sample surface, NMR measurement can be performed on an annular region along the circumference of an appropriate radius from the center of rotation.

Japanese Utility Model Sho 62-79151

Yasuto Noda et al., 7Li Microcoil MAS NMR Application to Cathode Materials for Thin-film Lithium Ion Batteries, 51st ENC (2010).

  Of the conventional methods for solid-state NMR measurement of thin film on the surface of a substrate, the most common method is that if a thin film sample is scraped off from a substrate and packed in a sample tube, it cannot be measured in the form of a thin film. There was a problem that the interesting physical properties obtained by taking the existence form as a laminated film were lost.

  On the other hand, the configuration of Patent Document 1 is similar to the present invention. However, Patent Document 1 has no data (information such as the obtained NMR spectrum, the amount of the sample, the size of the substrate, and the sample rotation speed) to show feasibility, and has a rotation speed of at least 10 kHz or more. It does not show the necessary building blocks for modern solid-state high-resolution NMR measurements (assuming to be implemented). In fact, there is no precedent for measuring thin film samples with such an apparatus.

  Above all, Patent Document 1 has a fatal defect. That is, the NMR transmission / reception coil of Patent Document 1 can measure only the inner part of the NMR transmission / reception coil, and when the NMR transmission / reception coil is arranged at a position other than the center of rotation, the measurement region becomes annular, and a correct high-resolution NMR spectrum is obtained. I can't get it. If the amount of the sample, the size of the substrate, and the size of the NMR transmitter / receiver coil are estimated from the diagram shown in Patent Document 1, it is assumed that the rotor diameter and the size of the NMR transmitter / receiver coil are approximately the same (generally, the NMR signal intensity is (In consideration of the fact that the sample is thin and the surface area is about the same as the rotor diameter, because the sample is proportional to the amount), the signal strength is estimated to be very small because the amount of sample is very small Is done.

  The configuration of Patent Document 1 requires a special NMR probe using an arm or the like and a special sample holder that can rotate. Therefore, it is difficult to think that it is versatile. In addition, there is almost no mention of the rigidity and balance of the sample holder. In the sample rotation mechanism, “swinging” may occur due to a delicate mechanical balance, which often hinders sample rotation.

  An object of the present invention is to provide a solid-state high-resolution NMR apparatus capable of measuring a large disk-shaped sample that does not enter a normal sample tube as it is in view of the above points.

  This is possible with a very simple configuration in which a “sample holder” for installing a thin film sample is installed at the end of a rotor used in a conventional NMR sample tube module. Furthermore, in order to irradiate the rotating thin film sample with a high frequency magnetic field, a surface coil placed on the high frequency circuit board for tuning and matching is brought close to the thin film sample, thereby irradiating a high frequency pulse and an NMR signal. Observation and detection are possible. Further, as a shape advantage of the surface coil, an optical laser or the like can be irradiated from a direction perpendicular to the surface of the thin film through the central space. Taking advantage of this advantage, it is possible to construct an experimental system for acquiring molecular structure information relating to the physical properties of the thin film by combining with an external field that changes the physical properties of the thin film.

  In order to achieve this object, a solid-state NMR apparatus according to the present invention includes a rotor having a cylindrical shape and holding a sample, disposed in a stator having an air bearing and disposed in a static magnetic field. A solid-state NMR apparatus for obtaining a solid-state NMR spectrum by irradiating a sample with an observation high-frequency pulse from an irradiation coil while rotating around an axis inclined at a magic angle with respect to a static magnetic field. A holding mechanism for removably attaching a sample holder for holding the coil is provided, and an irradiation coil holder for holding the annular irradiation coil is attached to the sample holder attached to one end of the rotor. Is configured to be detachably attached to the stator so as to face each other about the shaft.

  In addition, the sample holder is a disk-like shape, and includes a sample holding part in which a sample is attached to the surface of the disk or a sample is accommodated in an internal cavity of the disk, and a column part provided at the center of the back surface of the disk. Further, it is characterized in that it is attached to one end of the rotor by the locking mechanism through the support column.

  Further, the diameter of the irradiation coil is substantially the same as that of the disk-shaped sample holder.

  Further, the disk-shaped sample holder is characterized in that it rotates at high speed on a surface inclined by about 35.3 ° with respect to a static magnetic field.

  In addition, a thin film sample is provided on the surface of the disk-shaped sample holder.

  In addition, a powder sample is loaded into the internal cavity of the disk-shaped sample holding unit.

  The sample holder according to the present invention is a sample holder used in the solid-state NMR apparatus, and the sample holder is a disc-like shape, and the sample is attached to the surface of the disc or the sample is placed in the internal cavity of the disc. A solid-state NMR comprising: a sample holding portion in which the material is contained; and a support portion provided at the center of the back surface of the disk, and attached to one end of the rotor by the locking mechanism via the support portion. It is a sample holder for an apparatus.

  The solid-state NMR measurement method according to the present invention is characterized by measuring a solid-state NMR spectrum using the solid-state NMR apparatus.

  Further, at the time of the solid NMR spectrum measurement, at least one of laser beam irradiation, microwave irradiation, heat ray, hot or cold air irradiation, and power feeding by a wireless power feeding coil is performed on the sample held by the sample holder. Yes.

  According to the solid state NMR apparatus of the present invention, a rotor having a cylindrical shape and holding a sample is disposed in a stator that is disposed in a static magnetic field and provided with an air bearing, and the rotor has a magic angle with respect to the static magnetic field. A solid-state NMR apparatus for obtaining a solid-state NMR spectrum by irradiating a sample with an observation high-frequency pulse from an irradiation coil while rotating around an inclined axis at a high speed, and a sample holder for holding a sample at one end of the rotor And an irradiation coil holder that holds the annular irradiation coil is attached to the sample holder attached to one end of the rotor, and the irradiation coil is centered on the axis. Since it is configured to be detachably attached to the stator so as to face each other, a large disk-shaped sample that does not enter a normal sample tube can be left as it is. It has become possible to provide a constant possible solid-state NMR device.

  Further, according to the solid NMR measurement method of the present invention, since the solid NMR spectrum is measured using the solid NMR apparatus, a solid NMR measurement method capable of measuring a large disk-shaped sample that does not enter a normal sample tube as it is. It became possible to provide.

It is a figure which shows the conventional solid state NMR apparatus. It is a figure which shows the conventional solid-state NMR apparatus for wafer measurement. It is one Example of the sample holder for solid-state NMR measurement concerning this invention. It is one Example of the detection coil for solid-state NMR measurement concerning this invention. It is one Example of the solid-state NMR measurement part concerning this invention. It is a block diagram of the solid-state NMR apparatus concerning this invention. It is the example which measured the sample with the solid-state NMR apparatus concerning this invention. It is another Example of the solid-state NMR measurement part concerning this invention. It is another Example of the sample holder for solid-state NMR measurement concerning this invention. It is another Example of the solid-state NMR measurement part concerning this invention. It is another Example of the solid-state NMR measurement part concerning this invention. It is another Example of the solid-state NMR measurement part concerning this invention. It is another Example of the solid-state NMR measurement part concerning this invention. It is another Example of the solid-state NMR measurement part concerning this invention. It is another Example of the solid-state NMR measurement part concerning this invention. It is the example which measured the sample with the solid-state NMR apparatus concerning this invention.

  An object of the present invention is to perform solid-state high-resolution NMR measurement with high sensitivity in the form of a thin film without peeling off one thin film sample from a substrate.

  The conventional technique requires a special device having a sample turntable combined with a rotation mechanism. On the other hand, in the present invention, a rotating shaft of a “sample holder” for installing a thin film sample is fitted into a sample hole of a rotor used in a conventional NMR sample tube module and installed as an attachment. As a result, the object can be achieved with a very simple configuration.

  Further, in order to irradiate the rotating thin film sample with a high frequency magnetic field, the S / N ratio of the NMR signal is reduced by bringing a surface coil placed on the high frequency circuit board for tuning and matching close to the thin film sample. It can be optimized, and irradiation with a high-frequency pulse and observation / detection of an NMR signal become possible.

  In modern solid-state high-resolution NMR methods, sample rotation is required to be faster than 10 kHz (600,000 rpm). In this case, the rotational speed of the sample tube often decreases even by a slight deviation in the center of gravity. Therefore, in the design of the sample tube, the high rigidity (density, length, radius, wall thickness, concentricity) is very important in determining the performance.

  Therefore, I would like to emphasize that the method of rotating the sample by attaching something on the sample tube itself is outside the scope of the normal measurement method. The reason why the sample rotation speed does not increase is that the micro sample tube (glass capillary) has low rigidity (because the L / D ratio (the ratio of length to diameter) of the glass capillary is large). It was thought that the rotation of the sample occurred and the sample rotation was hindered.

Therefore, even if a sample holder having a size larger than that of a micro sample tube is attached, if the L / D ratio of the cylindrical portion supporting the sample holder is sufficiently large and the sample holder does not swing, the sample can be rotated at high speed. As a result, we succeeded in attaching a sample holder with a diameter of 7 mm to a rotor (sample tube) with a diameter of 4 mm and rotating at a frequency of about 7 kHz with a sample holder with a diameter of 12 mm. .
[Example 1]
The components necessary for carrying out the present invention are a “sample holder” and a “surface coil”. By attaching these configurations as an accessory to a unit of a conventional solid high-resolution NMR apparatus, solid high-resolution NMR of a thin film sample can be performed.

(1) Sample holder FIG. 3 shows an actually prepared sample holder for installing a thin film sample and a solid NMR sample tube to which the sample holder is attached. In the figure, reference numeral 32 denotes a disk-shaped sample holder, which is provided with a convex portion 33 at the center of the lower surface, and a circular sample 31 cut out in accordance with the diameter of the sample holder is attached to the upper surface with an appropriate adhesive. . The convex portion 33 of the sample holder 32 is fitted and locked into a concave portion 35 in which a sample is originally loaded for a commercially available solid NMR 4 mmφ sample tube (rotor) 34, and both are detachably integrated. Is shown. In addition, the sample holder may be fitted and detachably integrated so as to cover the upper end of the sample tube 34, and if both are locked by screwing, it is integrated more securely than fitting. Various modifications are conceivable for the locking method for attaching and integrating the sample holder to the sample tube.

  The shape and material of the experimental prototype are as follows.

  -Shape dimension: Circle-Diameter 7mmφ Thickness 0.5mm-2mm.

  -Material: Delrin (registered trademark).

  Other special notes: The thin film sample was a quartz substrate with an aluminum thin film deposited thereon, and was attached to the upper surface of the sample holder with an instantaneous adhesive (Aron Alpha (registered trademark)). The sample holder is fixed to the sample tube 34 only by fitting the sample holder 34 into the recess 35 of the sample tube 34.

  In the experiment, it was possible to rotate the sample with a thin film sample up to 11 kHz. When the sample was rotated further, Delrin (registered trademark), which is the material of the holder, was stretched by the influence of centrifugal force, and the substrate was stressed and destroyed. If the material of the holder is harder and lighter (preferably ceramics), the rotational speed can be further improved, and experimental conditions with higher resolution can be brought about.

  The metallic aluminum thin film was also successfully rotated at 7.5 kHz in a magnetic field of 7 Tesla. This shows that solid high-resolution NMR measurement of a metal thin film is possible. Applications such as sequential analysis of metal corrosion processes as well as solid high-resolution NMR of metals are expected.

(2) Surface coil A surface coil is the structure which wound the copper wire circularly on the same plane. In order to enhance the high-frequency magnetic field strength and the high-frequency magnetic field uniformity, the shape is preferably circular, but a rectangular shape can also be used. In the experimental prototype, the surface coil is attached to one surface of a circular circuit board, and a high-frequency circuit for adjusting the tuning / matching of the surface coil is provided on the other surface.

  FIG. 4 shows a circuit board 41 on which the surface coil 40 is mounted. FIG. 4A shows a surface on which the surface coil 40 is attached, and FIG. 4B shows a high-frequency circuit 38 for tuning and matching the high frequency irradiated with both terminals of the surface coil 40 connected. Indicates the surface to be placed. The circuit board 41 has a through hole 42 at the center and four holes 43 through which the mounting screws are passed. The surface coil 40 is attached to the substrate 41 so as to have the through hole 42 as the center, and both ends of the surface coil 40 penetrate the substrate 41 and are connected to the high-frequency circuit 38 on the back surface. Reference numeral 39 denotes a connector for connecting the high-frequency circuit 38 and the surface coil 40 to an external circuit. The shape and dimensions of the surface coil used in the experiment were a diameter of 7 mm, a wire diameter of 0.5 mm, 2.5 turns, an inductance of 84.5 nH, and a Q of 40 (281.8 MHz).

  (3) A component configuration for adjusting the position of the surface coil with respect to the target sample.

  In FIG. 5, a sample holder 32 according to the present invention and a circuit board 41 holding a surface coil 40 are attached to a sample rotation module 44 having a stator having an air bearing which is a unit of a conventional high-resolution NMR apparatus. The conceptual diagram of a mounting state is shown.

  A sample tube 34 (see FIG. 3) to which a sample holder 32 holding a sample 31 is attached is disposed in a static magnetic field, and is fixed to the two supports 100 so that the rotation axis has a magic angle with respect to the static magnetic field. The substrate 41 is placed in the sample rotation module 44 so that the surface coil 40 faces the sample 31 facing the sample rotation module 44 and is directly fixed to the sample rotation module 44 with screws 45. The surface coil 40 is arranged close to the sample surface to enable NMR measurement. The distance between the surface coil and the thin film sample is adjusted by a screw 45 that also serves to fix the substrate 41.

  This experimental prototype uses a commercially available sample tube, and a “blade” to which high-pressure gas is blown to obtain rotational force is attached to the lower part of the sample tube (rotor), so the sample holder on the upper side The installation of was relatively smooth. In the case of another commercially available sample tube in which the “blade” is mounted on the upper portion of the rotor, the hole is opened in the center of the “blade”, so that the sample holder can be attached.

  The measurement can be performed in the same manner as usual solid high-resolution NMR. That is, it includes a spectrometer system that integrates a control computer, transmitter, and receiver, a power amplifier, a duplexer, and an electrical circuit for irradiating a sample with a high-frequency pulse, and an NMR probe and solid powder for placing the sample in a magnetic field It is assumed that a standard solid-state high-resolution NMR system consisting of a sample rotation system for rotating a sample at high speed to obtain a high-resolution spectrum and a preamplifier for amplifying the NMR signal is used.

  FIG. 6 shows a schematic diagram of the solid high-resolution NMR system. The high frequency generated by the high frequency oscillator 101 is controlled in phase and amplitude time width (pulse width) by the phase controller 102 and the amplitude controller 103 and sent to the power amplifier 104 as a high frequency pulse.

  The high-frequency pulse amplified to the power necessary to excite the NMR signal by the power amplifier 104 is sent to the NMR probe 106 via the duplexer 105 and is not shown in the sample rotation system placed in the NMR probe 106. The sample to be measured is irradiated from the irradiation / detection coil.

  A weak NMR signal generated by the sample to be measured after the high-frequency pulse irradiation is detected by the irradiation / detection coil, sent to the preamplifier (preamplifier) 107 via the duplexer 105, and a signal that can be handled by the receiver 108. Amplified to intensity.

  The receiver 108 converts the high-frequency NMR signal amplified by the preamplifier 107 to an audio frequency that can be converted into a digital signal, and simultaneously controls the amplitude. The NMR signal frequency-converted to the audio frequency by the receiver 108 is converted to a digital signal by an analog-digital data converter (A / D converter) 109 and sent to the control computer 110.

  The control computer 110 controls not only the phase controller 102 and the amplitude controller 103 but also the sample rotation system 111 in the NMR probe 106 via a magic angle rotation (MAS) controller 112.

FIG. 7 shows a solid high-resolution NMR spectrum actually measured using the proposed apparatus. This is a ²⁷ Al MAS-NMR spectrum of a metal aluminum thin film by a thin film sample solid high resolution NMR measurement method. The spinning speed was 7.4 kHz, the carrier frequency was 78 MHz, and the integration time was about 12 hours.
[Example 2]
As shown in FIG. 8, the present invention can also be applied to solid state NMR measurement combined with light. It is possible to perform NMR experiments while photo-inducing functional substances and to combine with spectroscopy using light in a completely different energy region.

(1) Configuration Insertion of the sample tube 34 to which the sample holder 32 is attached into the sample rotation module 44 and attachment of the substrate 41 to the sample rotation module 44 are the same as in the example of FIG.

  As shown in FIG. 8, the thin film sample is irradiated with light on the sample holder from the direction of the sample rotation axis by a light guide system such as an optical fiber, a reflector, and a collimator. The substrate 41 interposed between the optical fiber 46 and the sample holder 32 has a through hole 42 in the center portion of the surface coil and there is no conductor or the like, and therefore does not block light. Accordingly, light may be irradiated through the through hole 42.

  In the case of a powder sample, it is possible to use a transparent sample holder 51 that transmits light made of quartz or the like shown in FIG. The sample holder 51 includes a flat cylindrical sample space 52 orthogonal to the rotation axis at the tip. It is possible to measure the powder sample by filling the sample space with the powder sample, inserting and fixing it in the sample tube, and rotating the sample holder at high speed.

(2) Operation The structure transferred by the optical chop (light on / off) synchronized with the NMR system is detected by the surface coil. It is useful for the analysis of new materials that undergo dynamic light-induced phase transition by turning light on and off. It is also useful for analyzing substances that act on light, such as resist materials. In the conventional apparatus, it is difficult to rotate the sample at a high speed while efficiently applying light to the sample. In the present invention, since the shape of the sample is thin and the surface area is large, it is possible to radiate light efficiently. It is also possible to rotate the sample at high speed.
[Example 3]
The present invention can also be applied to solid-state NMR measurement combined with μ wave as shown in FIG.

(1) Configuration Insertion of the sample tube 34 to which the sample holder 32 is attached into the sample rotation module 44 and attachment of the substrate 41 to the sample rotation module 44 are the same as in the example of FIG.

  A micro wave to millimeter wave to terahertz wave waveguide system 47 such as a μ wave waveguide and a μ wave resonator is applied to a thin film sample in a form that does not spatially interfere with the sample holder 32, the substrate 41, and the sample rotating module 44. Irradiate waves. The substrate 41 has a through-hole 42 in the center portion of the surface coil, and there is no conductor or the like, so that the μ wave is not directly blocked. Therefore, it is only necessary to irradiate the μ wave through the through hole 42.

(2) Operation Under a microwave irradiation, a change in NMR spectrum based on a change in physical properties of the thin film is directly measured. Sensitivity improvement in the vicinity of the surface can be performed by an effect such as DNP (dynamic nuclear polarization).
[Example 4]
The present invention can also be applied to solid state NMR measurement combined with heat, as shown in FIG. By directly changing the sample temperature, a temperature change NMR experiment can be performed in a temperature range that is difficult to achieve with a conventional probe.

(1) Configuration As shown in FIG. 11, a heat source 48 is placed on the sample holder 32, and the sample is directly heated and cooled with a hot wire. In this case, it is desirable that the material of the holder has a small thermal conductivity. The substrate 41 has a through-hole 42 in the center portion of the surface coil, and there is no conductor or the like, so it does not block heat rays. Therefore, the heat ray may be irradiated through the through hole.

(2) Operation It is possible to heat by directly applying hot air or laser to the sample. In addition, the sample can be cooled by spraying liquid nitrogen or liquid helium on the sample holder.

  In the conventional MAS experiment, there is no example in which the sample is directly heated and cooled. Only possible with the present invention where the sample is exposed. Therefore, it becomes possible to obtain an NMR spectrum in a temperature region that has been difficult to experiment until now. A MAS spectrum can be obtained when the sample is spot-heated to 1000 ° C. or higher by the laser heating method.

Since it is not necessary to heat the sample tube / experiment system as a whole, high-resolution solid-state NMR measurement under high temperature conditions can be facilitated, and in particular, contribution to inorganic NMR is expected.
[Example 5]
As shown in FIG. 12, the present invention can also be applied to solid state NMR measurement combined with a battery. NMR measurement in a charging / discharging process can be performed on a sample such as a thin film solid lithium secondary battery.

(1) Configuration As shown in FIG. 12 (a), a wireless power feeding coil 49 is installed around a region where the sample tube 34 is inserted in the sample rotation module 44, and as shown in FIG. 12 (b). In the case of the sample tube 34, the wireless power reception comprising a power receiving coil L that receives electromagnetic waves from the coil 49 and a diode that converts the AC voltage generated in the power receiving coil L into a DC voltage and a capacitor in the recess 35 that accommodates the sample. Provide a circuit. Then, the wireless power receiving circuit and the thin film solid lithium secondary battery attached to the sample holder 32 are connected by electric wiring, and a DC voltage is supplied from the wireless power receiving circuit to a sample such as a thin film solid lithium secondary battery so that the secondary battery is Charge. The wireless power feeding coil 49 is not necessarily arranged in the sample rotating module 44, and may be arranged around the sample holder 32 or may be arranged above the substrate 41. In such a case, the power receiving coil L is preferably disposed in the sample holder 32 so that the coil 49 can be well coupled. When the coil 49 is disposed above the substrate 41, power is supplied to the power receiving coil provided in the sample holder through the through hole 42 provided in the substrate 41.

(2) Operation A thin film on which a DC voltage is generated from a wireless power feeding coil 49 connected to an AC power source in a wireless power receiving circuit disposed inside the sample tube by mutual induction, and this DC voltage is placed on the sample holder. Supply to and charge a solid lithium secondary battery.

  In situ NMR of charge and discharge processes has been reported, but all have been measured in a static state without magic angle rotation, which is essential for solid high-resolution NMR. Magic angle rotation NMR, commonly known as MAS-NMR, is necessary to understand the macro properties of battery characteristics from the microscopic hierarchy of atoms and molecules.

  NMR spectra are extremely sensitive to physical parameters directly related to battery efficiency (mobility and electrical conductivity of lithium ions, changes in cation valence and electronic structure in the redox process). Furthermore, NMR can selectively measure elements and can be used to observe elements that are directly involved in battery operation. NMR spectra are sensitive to small changes in local structure and can follow non-destructively the structural changes associated with lithium ion deinsertion.

An important characteristic of NMR is that the integrated intensity of the NMR signal is proportional to the number of nuclei that resonate in the sample, so that it is quantitative. Therefore, if the NMR spectrum of each phase can be separated, the proportion of the relatively contained phase can be estimated quantitatively. Based on the above, by conducting high-resolution measurements while operating a lithium-ion battery, we can quantitatively track changes in local structure, valence and electronic structure associated with lithium ion desorption, and study the deterioration mechanism of battery characteristics. it can.
[Example 6]
The present invention can also be applied to solid state NMR measurement combined with a magnetic field gradient, as shown in FIG. Non-destructive thin film imaging can be performed.

(1) Configuration By arranging a gradient coil (not shown) around the substrate 41 or the sample holder 32, as shown in FIG. 13, a gradient magnetic field with respect to the sample rotation axis direction of the sample tube is generated, thereby reducing the depth of the thin film. Can be reflected in the NMR spectrum.

(2) Operation Acquisition of NMR spectra under a constant gradient magnetic field with a constant current flowing through the gradient coil, and acquisition of imaging information in the depth direction by the gradient pulse magnetic field by flowing a pulse current through the gradient coil Become.
[Example 7]
The present invention can also be applied to solid-state NMR measurement combined with an electric field, as shown in FIG. Solid state high resolution NMR measurements of the dielectric can be performed.

(1) Configuration The dielectric sample 31 is attached to the sample holder 32 and sandwiched between electrode plates 61 and 62 that are spatially separated. The electrode plate is attached to the surface of the substrate 41 to which the surface coil 40 is attached and the surface (upper surface) of the sample rotation module 44.

(2) Operation Solid high-resolution NMR of a dielectric under an electric field is measured by adjusting the distance between the electrode plates with a screw and measuring solid high-resolution NMR with a voltage applied between the electrode plates with a DC power source 63. Is possible.
[Example 8]
As shown in FIG. 15, the present invention can also be applied to solid-state NMR measurement combined with a gas phase reaction. Solid high resolution NMR of porous thin film materials can be performed.

(1) Configuration A porous thin film material is attached to the sample holder 32 as the sample 31, and a gas blowing system 65 is disposed around the sample holder 32 so that gas is blown onto the sample surface. A gas blower system 65 may be disposed above the substrate 41 so that gas is blown onto the sample surface via the through hole 42.

(2) Operation Since the gas can be directly blown onto the sample, the measurement can be performed with the gas uniformly adsorbed on the sample. It is useful for analysis of new materials expected as methane and hydrogen storage materials such as zeolite and porous metal complexes.

  It can be widely used for spectrum measurement of solid-state NMR. Conventionally, thin-film samples are measured by peeling them into powder, making thin films into small pieces, and packing them into conventional cylindrical rotors. There was a problem such as low.

  In contrast, according to the present invention, by attaching a thin film sample holder to the tip of the rotor, it is possible to measure with high sensitivity using a relatively large amount of sample and without changing the thin film state. Furthermore, since the sample is held perpendicular to the rotation axis at the end of the rotor, it is possible to irradiate the sample with laser light, microwaves, terahertz waves, various gases, etc. during measurement, and the structural changes of the thin film The fact that various reactions such as degradation and degradation mechanisms can be observed in situ can be said to be a highly inventive invention.

  The effects achieved by the present invention will be discussed in three stages: basic effects, applied effects, and industrial effects.

  (1) Basic effect: A thin film sample can be measured with high sensitivity and high resolution from one sheet.

  One thin film sample with a thickness of 2 μm and a diameter of 2.4 mm is not peeled off from the base material, but is measured with a conventional machine after being packed in a 4 mm rotor, and one thin film sample with a thickness of 2 μm and a diameter of 7 mm is measured with the present invention. Compare the cases.

  The S / N ratio of NMR cannot be simply discussed because the shape of the coil, the volume of the sample, the Q value of the NMR probe, the filling factor, etc. contribute complicatedly. However, since the filling factor and the Q value of the NMR probe are not so different from those of the conventional machine and the present invention, it is considered that the volume of the sample greatly contributes to the S / N ratio.

Therefore, roughly estimated, an S / N ratio increase of 8.5 times the same as the volume ratio of the sample can be expected. In this case, the time for acquiring the NMR signal is 1 / (8.5) ² = 1/72. In this prototype, the diameter of the thin film sample was 7 mm, but the sample holder with a diameter of 12 mm was also successfully rotated. In this case, a 25-fold increase in S / N ratio can be expected, and the experiment time is 1/625. This means that an experiment that takes 26 days can be done in one hour.

Originally, since the amount of sample of a thin film sample is very small, solid-state NMR measurement is very difficult, and there are almost no experiments. The present invention succeeded in ²⁷ Al MAS-NMR measurement of a 2 μm thin metallic aluminum thin film. The experimental data show that it is difficult to observe a thin film sample with a thickness on the order of nm because it takes a very long time at the site. However, the system created this time has not been optimized for sensitivity and resolution, and there is still room for improvement.

  In addition, it is extremely interesting from an academic and industrial viewpoint that unique structural information can be obtained by making a sample into a thin film shape. FIG. 16 shows (a) a solid high-resolution NMR spectrum of a metal aluminum thin film sample and (b) a normal solid high-resolution NMR spectrum of a bulk sample, which were measured by this experimental prototype.

(A) is the result of measuring ²⁷ Al-MAS-NMR of thin-film metal aluminum having a thickness of 2 μm at a spinning speed of 7.4 kHz, a carrier frequency of 78 MHz, an integration time of about 12 hours, and a probe Q value of 70, (b) It is the result of having measured the sample which mixed KBr for performing sample rotation smoothly in bulk metal aluminum.

The two spectra, although both observed ²⁷ Al nuclear metal aluminum, obviously have different sideband pattern of the spectrum, which change in electron state due to the sample into a thin film shape, the internal It shows that a dramatic change in the NMR spectrum was led by affecting and reflecting the interaction.

  As shown in this experimental example, the present invention provides unique molecular structure information derived from thin film shape by realizing in situ high resolution NMR of a completely non-destructive thin film sample. It is a revolutionary technique that makes it possible. This provides sample analysis and evaluation, quality assurance and development guidelines, and the impact on the entire industry for thin films is considered to be extremely large.

  (2) Applied effect: An external field can be applied by spatially separating the rotation mechanism and the measurement mechanism.

  As a shape advantage of the surface coil, an optical laser or the like can be irradiated from a direction perpendicular to the surface of the thin film through a central space. Taking advantage of this advantage, an external field effect such as light, microwave, electric field, gas injection, and laser heating that changes the physical properties of the thin film can be efficiently performed on the sample.

  For example, consider the case of laser heating. In the case of a normal NMR probe, there is a sample rotation module made of resin around the sample, and the temperature that can be heated was about 150 ° C. If a special probe for high temperature MAS (US Pat. No. 5,202,633) made of zirconia is used, a MAS experiment at 650 ° C. or higher is possible.

  On the other hand, in the case of the present invention, since there is no sample rotation module around the sample, the sample can be easily heated. If heating is performed locally using laser heating, the entire sample can be heated to 1000 ° C. in an instant.

  There is a technique called photoexcited triplet-dynamic nuclear polarization in which the sample is irradiated with microwaves and lasers to increase the NMR sensitivity by tens of thousands of times (K. Takeda, et al., J. Phys. Soc. Jpn , vol. 73, pp. 2313-2318). In the present invention, since the sample is thin, an optical laser can be applied efficiently. Therefore, it can be expected that polarization experiments can be performed efficiently.

  By performing high-speed rotation of the sample while performing such external action, solid-state high-resolution NMR of external action becomes possible. Further, by devising the shape of the sample holder, it is possible to perform solid-state high-resolution NMR of the external action of not only a thin film sample but also a powder sample.

  (3) Industrial effects: Industrial use (fields, products, equipment, methods, etc.).

  Currently, advanced thin-film devices having functionality such as thin-film lithium ion batteries, thin-film solar batteries, and organic EL are being actively developed. A thin film device is composed of a thin film material formed by stacking atoms and molecules on a substrate. The thin film material is a composite including the substrate, and even if only the thin film portion is taken out, the intended function is not exhibited. In order to measure the function, it is indispensable that the target state of the sample is a thin film on the substrate. Therefore, in device development, an understanding of the relationship between thin film materials in the final device state and device functions is strongly demanded.

  An electron beam, an X-ray, or the like is used for the structural evaluation of the thin film sample. Although the spatial resolution is high due to the short wavelength, there is a need to process the sample and measurement in a vacuum state due to the short permeation distance, and the sample state may change due to processing, or it may evaporate under vacuum. there's a possibility that. In addition, light elements having a small scattering cross section and amorphous materials having no periodic structure are not suitable for measurement.

  NMR provides extremely high information from the atomic and molecular level even for amorphous materials and light elements that are difficult to measure with electron beams and X-rays. Also, unlike electron beams and X-rays, radio waves with a low frequency are used, so almost all thin-film materials are transparent except when they do not penetrate due to superconductivity, and they are measured in the device state without destroying the sample. Is possible.

  However, in the conventional method, it is necessary to prepare many thin film samples according to the inner diameter of the sample tube for measurement, or in the case of one large thin film sample, it is necessary to peel or crush the whole substrate and fill the sample tube However, there is a point that the high cost and the non-destructive measurement which is an advantage of NMR cannot be utilized. A single sample matched to the inner diameter of the sample tube has a poor filling factor, so the sensitivity is low and measurement is impossible or takes a long time even if measurement is possible.

  In the present invention, even a single thin film realizes a sensitivity of 10 times or more. This means that the measurement time is reduced to 1/100. This not only improves the throughput, but also enables measurement of multi-dimensional NMR, which has been difficult to measure so far and can provide more information. Thereby, it becomes possible to measure without destroying the tip thin film device.

  Examples of the advanced thin film device include a thin film lithium ion battery. The market for thin-film lithium-ion batteries is in the testing phase in 2005, but is expected to reach 10 billion units and US $ 11 billion in 2012 (“Nanotechnology and Thin Film Lithium and Lithium Ion Battery Market Opportunities, Strategies , and Forecasts, 2006 to 2012 ”, WinterGreen Research, Inc.), there is a strong demand for evaluation technology to further improve characteristics.

  Although secondary batteries deteriorate with repeated charge and discharge, the mechanism is not clear. In conventional solid-state NMR, when measuring by charging and discharging a battery, it is performed with low resolution without rotating. In order to measure with high resolution, the battery is destroyed and the constituent material is taken out. However, it is thought that the deterioration mechanism of the battery is a local structure or phase change, and it is necessary to carry out with high resolution in order to quantitatively analyze them. Further, if the battery is destroyed, no further charge / discharge cycles can be performed. Therefore, non-destructive measurement is required in order to track deterioration that is a history phenomenon.

  The present invention can measure a thin film lithium ion battery in a device state with high resolution. Therefore, it is possible to provide a new means for quantitatively tracking the deterioration of the battery at the atomic level by repeating the cycle of charging and discharging and measuring with high resolution.

Examples of functional thin film devices that have already been industrialized include amorphous silicon solar cells and organic EL. In both cases, the correlation between the thin film material and the function is required in the state of the device, and the present invention is considered to contribute to the demand. Also, the sample spatially separates the rotating part and the sample part, Since various actions and operations can be easily performed from the outside, measurement can be performed in an environment where the device actually operates. In the case of laser heating, the oxide electrolyte used in the solid oxide fuel cell (SOFC), which is the most efficient fuel cell, is defective by performing solid-state high-resolution NMR at the operating temperature of SOFC of 1000 ° C. Can be analyzed.

  In a solid electrolyte, the structure of defects is directly related to the physical property of ionic conductivity, and is extremely important information for providing guidelines for material development and design. Solid-state high-resolution NMR is almost the only means that can analyze defect structures, and can be applied to the environment and energy fields such as batteries, gas sensors, and selectively permeable membranes.

31: Sample, 32: Sample holder, 33: Convex part, 34: Sample tube, 35: Concave part, 40: Surface coil, 41: Substrate, 42: Through hole, 43: Hole, 44: Sample rotation module, 45: Screw .

Claims (10)

A rotor having a cylindrical shape and holding a sample is placed in a stator that is placed in a static magnetic field and is provided with an air bearing, and the rotor has an axis inclined about 54.7 °, that is, a magic angle with respect to the static magnetic field. A solid-state NMR apparatus that obtains a solid-state NMR spectrum by irradiating a sample with an observation high-frequency pulse while rotating around at a high speed,
A locking mechanism for removably attaching a sample holder for holding a sample is provided at one end of the rotor,
An irradiation coil holder that holds the annular irradiation coil is removably attached to the stator so that the irradiation coil faces the center of the axis on the sample holder attached to one end of the rotor. A solid-state NMR apparatus comprising:   The sample holder comprises a sample holding part in which the sample is attached to the surface of the disk in the shape of a disk or the sample is accommodated in an internal cavity of the disk, and a support part provided at the center of the back surface of the disk, The solid-state NMR apparatus according to claim 1, wherein the solid-state NMR apparatus is attached to one end portion of the rotor by the locking mechanism via a support column.   The solid-state NMR apparatus according to claim 2, wherein the diameter of the irradiation coil is substantially the same as that of the disk-shaped sample holder.   The solid-state NMR apparatus according to claim 2, wherein the disk-shaped sample holder rotates at a high speed on a surface inclined by about 35.3 ° with respect to a static magnetic field.   The solid-state NMR apparatus according to claim 2, wherein a thin film sample is provided on the surface of the disk-shaped sample holder.   The solid NMR apparatus according to claim 2, wherein a powder sample is loaded into an internal cavity of the disk sample holder.   The solid-state NMR apparatus according to claim 1, wherein the irradiation coil holder has an opening at a position corresponding to a central portion of the irradiation coil. A sample holder used in the solid-state NMR apparatus according to claim 1,
The sample holder comprises a sample holding part in which the sample is attached to the surface of the disk in a disk shape or the sample is accommodated in an internal cavity of the disk, and a support part provided at the center of the back surface of the disk, A sample holder for a solid-state NMR apparatus, wherein the sample holder is attached to one end of the rotor by a locking mechanism via a support column.   A solid NMR measurement method for measuring a solid NMR spectrum using the solid NMR apparatus according to claim 1.   At the time of the solid NMR spectrum measurement, at least one of laser beam irradiation, microwave irradiation, heat ray, hot or cold air irradiation, and power feeding by a wireless power feeding coil is performed on the sample held on the sample holder. Item 10. The solid NMR measurement method according to Item 9.

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